/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: StringType.java,v 1.2.4.1 2005/09/05 11:35:57 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler.util;

import com.sun.org.apache.bcel.internal.generic.ALOAD;
import com.sun.org.apache.bcel.internal.generic.ASTORE;
import com.sun.org.apache.bcel.internal.generic.BranchHandle;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.GOTO;
import com.sun.org.apache.bcel.internal.generic.IFEQ;
import com.sun.org.apache.bcel.internal.generic.IFNONNULL;
import com.sun.org.apache.bcel.internal.generic.INVOKESTATIC;
import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
import com.sun.org.apache.bcel.internal.generic.Instruction;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.xalan.internal.xsltc.compiler.Constants;
import com.sun.org.apache.xalan.internal.xsltc.compiler.FlowList;

/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
public class StringType extends Type {

  protected StringType() {
  }

  public String toString() {
    return "string";
  }

  public boolean identicalTo(Type other) {
    return this == other;
  }

  public String toSignature() {
    return "Ljava/lang/String;";
  }

  public boolean isSimple() {
    return true;
  }

  public com.sun.org.apache.bcel.internal.generic.Type toJCType() {
    return com.sun.org.apache.bcel.internal.generic.Type.STRING;
  }

  /**
   * Translates a string into an object of internal type <code>type</code>.
   * The translation to int is undefined since strings are always converted
   * to reals in arithmetic expressions.
   *
   * @see com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo
   */
  public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
      Type type) {
    if (type == Type.Boolean) {
      translateTo(classGen, methodGen, (BooleanType) type);
    } else if (type == Type.Real) {
      translateTo(classGen, methodGen, (RealType) type);
    } else if (type == Type.Reference) {
      translateTo(classGen, methodGen, (ReferenceType) type);
    } else if (type == Type.ObjectString) {
      // NOP -> same representation
    } else {
      ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
          toString(), type.toString());
      classGen.getParser().reportError(Constants.FATAL, err);
    }
  }

  /**
   * Translates a string into a synthesized boolean.
   *
   * @see com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo
   */
  public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
      BooleanType type) {
    final InstructionList il = methodGen.getInstructionList();
    FlowList falsel = translateToDesynthesized(classGen, methodGen, type);
    il.append(ICONST_1);
    final BranchHandle truec = il.append(new GOTO(null));
    falsel.backPatch(il.append(ICONST_0));
    truec.setTarget(il.append(NOP));
  }

  /**
   * Translates a string into a real by calling stringToReal() from the
   * basis library.
   *
   * @see com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo
   */
  public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
      RealType type) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();
    il.append(new INVOKESTATIC(cpg.addMethodref(BASIS_LIBRARY_CLASS,
        STRING_TO_REAL,
        STRING_TO_REAL_SIG)));
  }

  /**
   * Translates a string into a non-synthesized boolean. It does not push a
   * 0 or a 1 but instead returns branchhandle list to be appended to the
   * false list.
   *
   * @see com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateToDesynthesized
   */
  public FlowList translateToDesynthesized(ClassGenerator classGen,
      MethodGenerator methodGen,
      BooleanType type) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();

    il.append(new INVOKEVIRTUAL(cpg.addMethodref(STRING_CLASS,
        "length", "()I")));
    return new FlowList(il.append(new IFEQ(null)));
  }

  /**
   * Expects a string on the stack and pushes a boxed string.
   * Strings are already boxed so the translation is just a NOP.
   *
   * @see com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo
   */
  public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
      ReferenceType type) {
    methodGen.getInstructionList().append(NOP);
  }

  /**
   * Translates a internal string into an external (Java) string.
   *
   * @see com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateFrom
   */
  public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,
      Class clazz) {
    // Is String <: clazz? I.e. clazz in { String, Object }
    if (clazz.isAssignableFrom(java.lang.String.class)) {
      methodGen.getInstructionList().append(NOP);
    } else {
      ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
          toString(), clazz.getName());
      classGen.getParser().reportError(Constants.FATAL, err);
    }
  }

  /**
   * Translates an external (primitive) Java type into a string.
   *
   * @see com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateFrom
   */
  public void translateFrom(ClassGenerator classGen,
      MethodGenerator methodGen, Class clazz) {
    final ConstantPoolGen cpg = classGen.getConstantPool();
    final InstructionList il = methodGen.getInstructionList();

    if (clazz.getName().equals("java.lang.String")) {
      // same internal representation, convert null to ""
      il.append(DUP);
      final BranchHandle ifNonNull = il.append(new IFNONNULL(null));
      il.append(POP);
      il.append(new PUSH(cpg, ""));
      ifNonNull.setTarget(il.append(NOP));
    } else {
      ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
          toString(), clazz.getName());
      classGen.getParser().reportError(Constants.FATAL, err);
    }
  }

  /**
   * Translates an object of this type to its boxed representation.
   */
  public void translateBox(ClassGenerator classGen,
      MethodGenerator methodGen) {
    translateTo(classGen, methodGen, Type.Reference);
  }

  /**
   * Translates an object of this type to its unboxed representation.
   */
  public void translateUnBox(ClassGenerator classGen,
      MethodGenerator methodGen) {
    methodGen.getInstructionList().append(NOP);
  }

  /**
   * Returns the class name of an internal type's external representation.
   */
  public String getClassName() {
    return (STRING_CLASS);
  }


  public Instruction LOAD(int slot) {
    return new ALOAD(slot);
  }

  public Instruction STORE(int slot) {
    return new ASTORE(slot);
  }
}
